Reading Time: 10 minutes

When we lived in Minneapolis, our family used to take walks through an area called the Quaking Bog. On one fall walk, I spotted a fawn and waved the kids over. “Look, look. See the deer?” I said. “You can just barely see it against the leaves!”

Erin said, “It’s almost invisible.”

She was about eight years old, her sister Delaney four years old, said, “Wow. If I was a aminal that ate deers, I’d never see them. I’d just starve.”

I said, “Unless there was a bright pink one.” They both laughed, and the deer bolted.

“Oh good job, girls.” (That wasn’t me. That was older brother Connor, who was about 10.)

“Okay,” I said, “pink and slow. I think I’d eat nothing but slow, pink deer. And pretty soon there’d be no more slow pink deer, just the ones that blend in better and run fast.”

In my nonreligious parenting workshops, I’m often asked how to talk to really young kids about evolution, three or four years old, how do you do it? And I always say, you don’t. Then they get mad. And I elaborate.

What I mean, of course, is do teach them about it. But do it in the same way you might teach a young kid about a Shakespeare sonnet or a Bartók string quartet. I wouldn’t sit a kindergartener down in front of Bartók’s Fifth Quartet and expect her to plead please oh please Daddy for the Sixth Quartet.

The trick is to lay a groundwork by exposing her to music of a hundred kinds, so that later, when she encounters Bartók, she’ll have the experience and the conceptual grounding to make her own informed judgment about it. Appreciating Shakespeare starts with exposure not to Sonnet 138, but Green Eggs and Ham.

Get them having fun with meter and rhyme and wit. Then they’ll step up into more and more subtle examples of it very naturally as their palette matures.

To understand why Bartók and Shakespeare are so incredible, it helps to have come across a thousand other examples of their respective arts to get a sense of what’s possible and what’s been tried. Then you can really savor what they did.

Evolution is another thing that’s best approached in sensible steps. It’s an immense, complex, and subtle thing that takes place in achingly slow increments as random variation is acted upon by non-random selective pressures. It’s directional in the short term and directionless in the long term. It is heartless and wasteful and elegant all at once.

Don’t start with evolution

In my early teens, I had a very basic grasp of evolution. Then I majored in evolutionary anthropology in college because I knew just enough to know how much I didn’t know and how much I wanted to know it.

So I was about 20 before I really had a solid grasp of evolution, its evidence, its mechanism, and its astonishing implications.

From the beginning, my kids were on track to beat me in everything else: looks personality, sports, general maturity, fashion sense. So I wanted to do what I could to help them grasp the greatest realization in human history a lot earlier than I did as well.

But if you start with evolution, you have to simplify it, right, for young kids. And when you simplify it, it’s just weird. You say things like “A long time ago, animals turned into people.” And they start looking at Grandma funny. They don’t have the foundational concepts they need to understand what that means. So the answer is to teach evolution the same way it happens: in small steps over many years.

And you focus not on evolution first, but on adaptation.

Start when they are really young by drawing your kids’ attention to adaptations of all kinds constantly. every chance you get. The deer in the woods was an example of camouflage—markings that help an animal blend into the background. That’s one of the most common adaptations in nature and one of the easiest for kids to understand.

Treefrog Hyla marmorata in the Peruvian rainforest

A good activity to drive this one home is the camouflage egg hunt at Easter (or whenever). Color a dozen hard-boiled eggs in green and brown and leave another dozen plain white. Then hide all 24 around the backyard or park and turn the kids loose. As they bring the eggs back to you, put them in the order they are found. Most of the white ones will be found first. Depending on the age of the kids, you can prime the pump with a little conversation: Man if I was a predator, hunting for eggs, I’d find all the white ones first, and pretty soon there wouldn’t be any more etc etc. Right? Just like the pink deer. So that’s camouflage.

Mimicry is another thing to watch for and talk about. Moths with huge spots on their wings that look like scary eyes so birds are afraid to eat them. The walking stick that looks like a twig. Mimicry.

Speed, like the fast deer I couldn’t eat. Deception, like a possum playing dead. Protection, like armadillo plates or porcupine spines, sharp hearing or sight or smell.

Then you can talk about sexual selection, what makes one individual attractive to another: plumage or mating dance, a particular call, or a steady job.

Then for every adaptation, imagine a poor one. Hey, what if the deer was bright pink? What if it was slow? Those are poor adaptations.

And then all those adaptations set the stage for natural selection itself.

Evolution itself requires thousands of generations and a massive timescale that kids won’t immediately comprehend. Kids to whom 2017 was a long time ago have trouble with all that.

And above the microbial level we can’t see evolution in action anyway, but we can study natural selection, the mechanism by which evolution occurs.

Once natural selection is understood, evolution is an inevitable consequence of the passage of time. And one creature in particular is just waiting in the wings (so to speak) to explain natural selection to our kids: the peppered moth.

How to tell the story of the peppered moth

There is a moth in England called the peppered moth. Two hundred years ago, most peppered moths were light gray, with black and brown speckles all over them like somebody had peppered them.

That worked out fine for the moths. It made them blend in with birch tree bark that was light gray was speckles, so it was hard for birds to find them and eat them.

But there were also a few peppered moths that didn’t look peppered at all. They were completely black. But only a few. You can probably guess why: The black ones didn’t blend in very well against the light-colored tree trunks. So they were dinner for the birds.

If someone has you for dinner, you aren’t going to have too many babies. And since the black moms were being eaten the most, there were never too many black baby moths being born.

And then something interesting happened: Big factories were built in the town near the moths’ forest in central England. Dark black smoke belched out of huge smokestacks, making the air near the town very dirty. And the bark on the trees in the moths’ forest turned completely black from the dirty factory smoke.

That made things a little different from the mods. Now the black mods were almost invisible on the black tree trucks and the light-colored moths were so easy to see.

(Now stop at this point in the story and see if the child can give you the next step. Ten bucks says yes.)

Birds only eat what they can find. So who are they eating now? The light-colored ones! The black moms were pretty happy about this. Now more of their babies can be born and stay safely hidden from the birds on the black tree trunks. After about 20 years, people noticed that almost all of the moths in the forest were now black.

Now only a few were light gray. The peppered moth had been changed, all because its environment changed.

You can tell the story in a dozen ways depending on the age and level of your child. But some kids as young as six years old will excitedly follow its logic and grasp the implications. Ask what they think will happen to the moths when the factory closes and the black soot washes off the tree trunks, which did in fact end up happening in the mid-20th century. And yep, the phenotypes switched back again.

Ask if they think one color of moth would ever disappear completely. Tell them the whole process is called natural selection and ask if it makes sense.

Ask if they think this only happens to moths, or might it just apply to lizards as well or hippos or…humans?

Now, you will hear from a lot of creationist websites that the peppered moth has been debunked. They’ve actually spent a tremendous amount of time going after this for obvious reasons, because it’s really good and accessible and clear and kids understand it.

But it hasn’t been debunked—it’s been greatly reinforced.

An original experiment, and then even better-designed experiments afterward, have confirmed and reconfirmed the original hypothesis of what happened to the peppered moths.

In his book Moths, Cambridge biologist and moth melanin expert Michael Majerus sums up the consensus in the field: “I believe that without exception, it is our view that the case of melanism in the peppered moth still stands as one of the best examples of evolution by natural selection in action.”

The rise and fall of the legend of the heike crabs

In the original Cosmos series, Carl Sagan shared the story of the heike crabs of Japan that were said to contain the souls of defeated samurai warriors from a great battle. And some of the markings on the shell vaguely resembled a samurai’s face.

So when the fisherman would pull up a net of fish, and there were some crabs in the net, the more the markings resembled an actual face, the more likely they were to throw it back in the water. Over time, this process of artificial selection would have resulted in a more and more face-like pattern on the crabs. And now if you look at a heike crab, it looks a lot like a scowling samurai.

So I told my kids this story, and they loved it, and they understood it. And several years later, it was called into question in a credible way by a researcher who noted that the heike crabs were not actually consumed for food. It was unlikely that this particular selective pressure took place.

That was a bummer. I liked the story. But I told my kids about this new information so that they’d understand how science works.

The power of analogy

Finally, you can use analogies to teach the otherwise unimaginable timescale required for evolution. Analogies can be hard for really young kids, but once they’re able to handle that level of abstraction, there’s no better way to render the inconceivable conceivable.

Saying that a million Earths would fit inside the Sun, that’s fine. But saying if the Sun were a soccer ball, Earth would be a peppercorn—now I get it. And analogies can also help kids grasp those huge timescales, one of the conceptual requirements for understanding evolution.

Carl Sagan suggested compressing the 13.8 billion-year history of the universe into a single year. New Year’s Day at midnight was the Big Bang. And today, it’s December 31, New Year’s Eve, one second before midnight, going into the next year. Each day is 37 million years long.

We all have days like that.

One thing you can do with your kids is actually get one of those big oversized calendars and put the Big Bang on January 1 and put us today in the lower right-hand corner of December 31. And then ask them: where do the dinosaurs go on this? Where do you think the first trees go? When did Earth form? When did the Milky Way galaxy form?

When did humans happen?

When I was a kid, I think I would have said Earth forms in February, plants in March, dinosaurs in April, people in May. Something like that.

In fact, the Milky Way galaxy doesn’t form until around May 1 on this compressed calendar.

Our solar system came to resemble the solar system around September 9th.

Earth’s birthday was on September 14.

Humans can safely be considered unimportant during this 8 billion-year period, before we even had a planet.

Once the planet did come together, life was amazingly quick to sprout up appearing just 400 million years later on September 25th. No, not dinosaurs, microscopic waterborne life. They ruled the earth until November 12, when tiny undersea plants took the throne. By December 1st, these plants and bequeathing an oxygen atmosphere to the planet.

You ready for dinosaurs? That’s so cute. You’re like a little kid. Thirty-ton lizards do not spring into being from microorganisms. There’s work to be done, and this kind of work takes time. By December 16, just eight shopping days until Christmas, we’ve reached a critical step on the road to us.


By December 19, we’ve got fish land plants, on the 20th insects on the 21st amphibians on the 22nd.

Surely I’ve made a mistake: Only nine days left in the year, and still no lords of the universe?

On the 23rd the first trees come to pass. And at last on Christmas Eve, your beloved dinosaurs begin their 180 million-year reign of terror. December 28, an asteroid slams into Chicxulub on the edge of the Yucatán.

Also flowers are invented.

Oh, and humans? Lemme check.

Okay, here it is: On the scale of a single cosmic year, the genus Homo came into being at 10:30 pm on December 31, because 90 minutes, 90 minutes out of the year. That’s Finding Nemo with one potty break.

But that still isn’t really us. Our actual species, Homo sapiens, arrived at 11:51 pm.

Nine minutes ago.

Feeling special?

As for recorded history, agriculture was invented 40 seconds ago. The first Egyptian dynasty started 10 seconds ago. The Roman Empire spans an admittedly impressive two seconds, and the Renaissance happened one second ago.

Now we’ve got a little better understanding of time. Then Richard Dawkins created another one of these analogies for the history of life on Earth. Have your child stretch her arms out to represent the span of the history of life on Earth, from her left fingertip all the way across the middle, to well past her right shoulder. life consists of nothing but bacteria. At her right wrist, the most complex form of life on Earth is worms.

Dinosaurs appear in the middle of her right palm and go extinct around her last finger joint. The whole story of Homo sapiens, our species is contained in the thickness of one slim fingernail clipping. All of recorded history is blown away in the dust from a light stroke of a nail file.

There’s the epic canvas of time on which evolution can play out.

So that’s been our approach. And once in a while, as my kids were growing up, I would get a hint that it was working.

One time when my son was 14, I saw him just staring blankly out our back window. And then suddenly he said, “Dad! Plants don’t feel pain.”

And I said, “Oh, how do you know that?”

He said, “There’d be no reason for them to evolve that. Pain is a warning so you can get away from something like a predator or take your hand out of the fire, but plants can’t move anyway. So pain wouldn’t give any advantage. It wouldn’t help one plant survive to reproduce more than another one. It would just hurt.”

I reel in moments like these.

Never mind whether he’s right. I have no idea if he’s right. The wonderful thing is that he was thinking creatively and in real evolutionary terms with that grounding. And once he encountered evolution in greater depth, it just slipped on like a glove.

Evolution for breakfast

One morning as his sisters were eating breakfast, I opened the bottle of their chewable vitamins.

“I want an orange one!” said Erin. “I’m well aware,” I said. “

Me too!”

I said, “Lanie, I know what color you want. Girls, you tell me every morning.”

I tap two vitamins into my hand. Both purple.

I poured out a bunch more. All purple.

“Of course,” I said, showing the handful of purple vitamins.

And Erin chuckled. “Well that’s because we asked for orange every day.”

Suddenly her eyes got really big. “Oh my gosh, it’s just like the heike crabs!”

And I realized it was. The purple vitamins were like the crabs with the most face-like pattern. And each time we pulled one out, we threw it back in until that’s all that was left.

I had wanted an experiment that captured the concept of the heike crabs, and we created one at the breakfast table.

Avatar photo

Dale McGowan is the author of Parenting Beyond Belief, Raising Freethinkers, and Atheism for Dummies. He holds a BA in evolutionary anthropology and a PhD in music.